A painting and preparation question...pitted steel on roof...filler...?

[Barge Maria]

I hope some of you experienced boat painters can advise me please.

 

I am treating the rust patches on the rear cabin roof of our barge prior to repainting. I have scraped off the rust back to good metal in the places that need it, and treated with Vactan. Nice purple/black patches now!

 

However, this has of course left indentations, as most of the rest of the paint is good and only needs a sand down and repaint (Epiphanes one pack paint).

 

Another barge owner suggested a marine filler, designed for smoothing surface imperfections, should be used before priming these patches and general sanding. I'm happy to do this, and have bought some at extortionate Belgian prices, BUT am worried about the differential expansion of the steel roof and the filler. The roof is light cream but still gets very hot in summer and Epiphanes is too expensive to waste on a finish that falls out or puckers up under heat stress.

 

So, what do more experience folk think?

 

To fill or not fill, that is my question!

 

Thanks in anticipation.

 

Tim

[bag 'o' bones]

Unless your troweling the filler on an inch thick you won't have a problem. Styrene based fillers are designed to expand and contract along with the steel. You do need to provide a key for the filler to attach to so give the Vactan a quick roughen up to break the glaze. It won't hurt if you break through to bright steel.

Edited September 14, 2014 by bag 'o' bones

[Barge Maria]

Thanks B 'o B,appreciated. Its only a thin layer and in fact the instructions do say apply in thin layers (in Dutch!).

 

Well give it a try.

 

Dank u vell!!

 

Tim.